A wireless fidelity (WiFi for short) technology is a main technical standard of a wireless local area network (WLAN for short). The technical standard 802.11 formulated by the Institute of Electrical and Electronics Engineers (IEEE for short) is technically more mature after developing into various versions such as 802.11a, 802.11b, 802.11d, 802.11n, and 802.11ac, and a transmission speed is higher. In another aspect, due to unique flexibility of the WiFi technology, the WiFi technology is increasingly applied in household and commercial environments. In a WiFi-based WLAN network, a receiver performs a baseband processing procedure on a received signal, mainly including: symbol synchronization, channel estimation, data preprocessing, and the like. The symbol synchronization refers to performing symbol synchronization according to a received short training field (STF for short) and the received signal to implement frequency synchronization and time synchronization between a transmitter and a receiver. The channel estimation actually uses a received long training field (LTF for short) to perform channel estimation so as to obtain channel information. The data preprocessing actually refers to performing channel equalization on a signal according to the channel information obtained by means of the channel estimation, so as to eliminate channel impact. Although the receiver may use the STF to implement frequency synchronization between the transmitter and the receiver, due to existence of noise and interference, a residual frequency deviation still exists after a frequency between the receiver and the transmitter undergoes synchronization processing according to the SFT. Although the receiver may eliminate channel impact according to channel equalization in data preprocessing, the residual frequency deviation still exists. The residual frequency deviation may lead to a phase deviation of a received signal, and further lead to increase of a bit error rate of the received signal or even failure in demodulating the received signal.
In the prior art, a pilot may be carried on a pilot subcarrier, and a phase deviation may be estimated according to the pilot, so as to obtain the phase deviation. The receiver performs phase compensation for the channel-equalized data according to the obtained phase deviation to relieve impact caused by noise and interference. In a multiple-input multiple-output (MIMO for short) scenario of uplink multiple users, that is, in a scenario in which there are at least two stations and an access station includes at least two antennas, stations each transmit different pilots to the access station by using their respective antennas. Therefore, a process of obtaining a phase deviation between each station and the access station by the access station is actually a process of solving, according to a received signal on a pilot subcarrier and a pilot, a matrix of multiplying a quantity of data flows of all stations by a quantity of receive antennas of the access station.
However, the larger quantity of uplink data flows transmitted by all stations indicates the more complex process of solving the phase deviation between each station and the access station by the access station.